Frequency sweep from 1hz - 100khz, output was stable, after 10khz you could start to see some delay in rise time but, everything still functioned.

There was a 50ma load on the mosfet during this test. Not sure if a larger load will affect things (test latter).

Pwm Current Table For a 5cm Segment of RGB Led's (edit) VCC:12vdc, PWM signal: 5vdc

so.... around 100hz+ the current is effectively halved?, yay! science!

photos